Did Chevy make a 405?
A Chevrolet-branded car or factory engine officially designated as “405” does not exist in Chevrolet’s production history. The number 405 is not a formal model name or displacement used by Chevy for a mass-market vehicle or factory engine.
What “405” could refer to in Chevrolet lore
Several contexts outside an official model or engine name can lead people to encounter the number 405 in connection with Chevrolet. The following list explains the common sources of confusion and why they are not an official Chevy designation.
Common sources of confusion
- Horsepower claims from old advertisements or magazine tests, which sometimes quoted numbers in the 400s. These figures reflect rating methods and tune levels rather than a distinct model or engine code named “405.”
- Aftermarket crate engines or performance packages that players or sellers might label with “405,” either as a target horsepower or displacement. These are not factory Chevrolet model designations.
- Internal option or service codes that include numbers such as 405 in documentation or parts catalogs. Such numbers rarely map to a publicly marketed model name and can be misinterpreted as a model number.
In short, while you may encounter the number 405 in Chevy-related contexts, it does not denote a production Chevrolet model or a factory-displacement engine with that exact designation.
How to verify if a vehicle or engine is truly a “405” Chevrolet
If you suspect a vehicle or engine is labeled as “405” and want to confirm what it really is, use these steps to verify authenticity and avoid mislabeling.
Verification steps
- Check the VIN, engine code, and body tag against the vehicle’s build sheet or window sticker to determine the official model name and displacement for that year and trim.
- Inspect the engine block for displacement stamps or suffix codes and compare them with Chevrolet’s historical reference guides or trusted databases.
- Consult official Chevrolet documentation, such as the era catalogs, Chevrolet Heritage Center resources, or reputable automotive histories, to confirm which displacements and horsepower figures were offered for the relevant model year.
- If in doubt, consult a certified Chevrolet dealer, a recognized automotive historian, or a qualified restoration expert who can cross-check the build data and parts compatibility.
Following these steps helps determine whether a label or claim of “405” corresponds to an actual factory designation or is a misinterpretation of horsepower, option codes, or aftermarket labeling.
Summary
Chevrolet has not produced a mainstream model or factory engine officially named “405.” The appearance of the number in various materials typically reflects horsepower ratings, aftermarket labeling, or internal codes rather than a distinct Chevrolet production designation. For accuracy, rely on VINs, build sheets, and authoritative Chevrolet histories to verify any such claim.
Did Chevrolet ever make a 400 big-block?
No, Chevy did not make a "400" big block, but they did make a large, powerful 402 cubic inch big block and a 400 cubic inch small block engine around the same time, which caused some confusion. From 1971 to 1973, Chevy sometimes used "400" in its advertising for the 402 big block, which was officially known as the "Turbo-Jet 400" (while the 400 small block was the "Turbo-Fire 400").
You can watch this video to learn about the history of the Chevy small-block 400: 56sRare Classic Cars & Automotive HistoryYouTube · Aug 31, 2023
Chevrolet's 400 cubic inch engines
- 400 Small Block: This engine was produced from 1970 to 1980 and was the largest displacement for the small block family. It was designed for low-end torque, making it well-suited for heavy cars and trucks.
- 402 Big Block: This was the actual displacement of the big block engine that was sometimes marketed as a "400". It was part of the Mark IV big block V8 line, produced from 1970 to 1972.
Why the confusion?
- In marketing materials, especially from 1971-1973, Chevy used the "400 Turbo-Jet" designation for the 402 big block to avoid confusion with the smaller engines, but it was still a confusing marketing decision.
- The existence of two 400 cubic inch engines in different engine families (one small block and one big block) was a source of confusion for car enthusiasts.
What motor is a 405?
As with the BX, the 405 used TU/XU petrol and XUD diesel engines.
What is the rarest Chevrolet engine?
The rarest Chevy engines are the 1969 ZL1 427 V8 and the 1963 Z11 427 V8. The ZL1 is arguably the rarest due to its extreme performance and high cost, with only 69 factory-built aluminum V8s produced for racing. The Z11, also a 427 V8, was an even earlier and more limited production model, with fewer than 40 units built in 1963.
You can watch this video to learn about the 1969 ZL1 engine, one of the rarest Chevy engines ever built: 55sIts Just Cars!YouTube · Jul 15, 2025
1969 ZL1 427 V8
- Production: Only 69 were built, all with aluminum blocks.
- Features: Included forged internal components, high-flow heads, and a transistorized ignition.
- Performance: Officially rated at 430 hp, but was unofficially capable of over 500 hp.
- Rarity: Its high cost made it a rare option, and it was developed to bypass GM's "no racing" policy.
1963 Z11 427 V8
- Production: Extremely limited production, with fewer than 40 units created.
- Features: An enlarged 427ci version of the 409 engine with taller heads and aluminum intake manifold and water pump to save weight.
- Performance: Produced 430 hp.
- Rarity: This was a limited-production run, making it Chevrolet's rarest engine of all time.
Did Chevy make a 305 engine?
Chevrolet's 305 small-block was created to assist with fuel efficiency in mind, which can affect power. However, this little V8 engine could do so much more. StockeyRacing exactly what I was about to say. I've you've lived with one long enough, you know why many got swapped for 350s & 383s (or pick any LS/LT today).
